THIS REMARKABLE INDUSTRIAL CORRIDOR JUST east of Chicago is the largest concentration of steel plants in the world. Five major complexes, and numerous smaller related industries, are grouped along a 20-mile strip of Indiana, following US Highway 12 at the southern shore of Lake Michigan.

The industry developed in this region for obvious reasons: to take advantage of shipping routes, both on land and on the Great Lakes; to be near population centers; and to be close to the users of steel products, primarily the construction, appliance, and automotive manufacturing industries.

Field researcher Suzanna Mast photographed and explored this superlative industrial landscape for The Center, and submitted a thorough report.

1. LTV Steel, the nation's third largest steelmaker, employs 4,000 people at its Indiana Harbor Works plant in East Chicago.

2. Among the largest steel plants in the nation, Inland Steel's Indiana Harbor Works, also located in East Chicago, covers 1,900 acres and employs 10,000 people to produce up to 6 million tons of steel products annually.

3. U.S. Steel's Gary Works is also one of the largest steel plants in the country, employing 8,000 people. It is owned by USX, the largest steel company in the nation.

4. Rather than manufacturing steel, this Midwest Steel Plant in Burns Harbor finishes steel at this location, using steel manufactured by the company at plants near Detroit and St. Louis. The parent company, National Steel, is the fourth largest steel company in the country.

5. Immediately east of the Midwest Steel plant is Bethlehem Steel Burns Harbor Plant. Built in 1962, this facility employs 6,000 people in making hot-rolled and cold-rolled sheet steel for the automotive, container, appliance, and other industries. Bethlehem is the second largest steel producer in the country.